Special Issue Editor

Special Issue Information

Dear Colleagues,

Hygienic waste and wastewater disposal is essential for human civilizations. Current waste and wastewater disposal practices in developed nations are both excessive energy and water consuming, hence not sustainable. The increasing scarcity of water and energy in the developing world along with rapid population increase in urban areas gives reason for concern and the need for appropriate water and energy management practices. Currently there is a growing awareness of the impact of waste and wastewater contamination on rivers and lakes. The developing world with over three billion people is simply attempting to duplicate those unsustainable waste and wastewater disposal practices. Both waste and wastewater contain water and energy that can be harvested. In addition both contain nutrients that can be use as fertilizer. There are several emerging technologies for waste and wastewater disposal that are sustainable with minimal ecological footprint. The objectives of this special issue are first educate the reader of the unsustainable nature of the current waste and wastewater disposal practices, and how to make them sustainable while those methods are hygienic so that we could leave a livable planet for our children and their children.

Abstract: Spreading sewage sludge from municipal wastewater (MWW) treatment on land is still a common practice in developing countries. However, it is well known that sewage sludge without special treatment contains various pollutants, which are (re)introduced into the environment by sludge landspreading and which might in turn have harmful effects on the environment and human health. This is more dangerous in places like Merida, Mexico, where soil is calcareous with fractures along the ground and thin layers of humus. Consequently, any liquid and semisolid wastes have the potential of percolating to the subsurface and contaminate the aquifer. The main aim of this work was using composting as a low cost process to eliminate pathogens contained in sewage sludge from MWW treatment in order to use the final product for land spreading in a safe way for both environment and human health. Two piles for composting process at real scale were settled using a mixture of sewage sludge from municipal waste water and green waste. Composting was carried out by windrow process and it was monitored during four weeks. Concentration of helminth eggs, salmonella and faecal coliforms were measured twice a week to observe its behavior and, as a control process, Temperature, Moisture Content (MC), and pH were also measured. After 30 days of composting sludge from municipal waste water system, salmonella was eliminated by 99%, faecal coliforms by 96% and helminth eggs by 81%. After 3 months compost reached GI = 160%, so did not show any phytotoxicity to seeds.

Abstract: Membrane Bio Reactors (MBRs) are mainly used for industrial wastewaters applications where their costs can be more easily afforded. High costs are basically due to energy consumption and membrane cleaning or replacement. Membrane fouling is responsible for reducing treated water production and increasing maintenance as well as operation costs. According to previous researches, the addition of Powdered Activated Carbon (PAC) in high dosages could reduce membrane fouling; but such concentrations are economically unsustainable for operative conditions. A MBR pilot plant, fed by mixed liquor of a full-scale activated sludge process from a municipal wastewater treatment plant, was operated dosing low PAC concentrations (0, 2, 5, 10 and 20 mg·L−1, respectively). Experiments were also carried out at two different temperatures corresponding to summer and winter conditions. Results indicated that PAC addition was effective at the low dosages (2 and 5 mg·L−1) by reducing the permeate flux loss (from 16 up to 27%, respectively) while higher PAC concentrations turns out in a useless cost increase.

Abstract: The aim of this paper is to suggest and discuss policy instruments that could lead towards a more sustainable waste management. The paper is based on evaluations from a large scale multi-disciplinary Swedish research program. The evaluations focus on environmental and economic impacts as well as social acceptance. The focus is on the Swedish waste management system but the results should be relevant also for other countries. Through the assessments and lessons learned during the research program we conclude that several policy instruments can be effective and possible to implement. Particularly, we put forward the following policy instruments: “Information”; “Compulsory recycling of recyclable materials”; “Weight-based waste fee in combination with information and developed recycling systems”; “Mandatory labeling of products containing hazardous chemicals”, “Advertisements on request only and other waste minimization measures”; and “Differentiated VAT and subsidies for some services”. Compulsory recycling of recyclable materials is the policy instrument that has the largest potential for decreasing the environmental impacts with the configurations studied here. The effects of the other policy instruments studied may be more limited and they typically need to be implemented in combination in order to have more significant impacts. Furthermore, policy makers need to take into account market and international aspects when implementing new instruments. In the more long term perspective, the above set of policy instruments may also need to be complemented with more transformational policy instruments that can significantly decrease the generation of waste.

Abstract: This paper reports a life cycle assessment undertaken to assess the environmental impact of a range of biosolid reuse options selected by the Kaikōura community. The reuse options were identified as: vermiculture and open-air composting; mixture with biochar; direct land application to disturbed sites for forestry using native tree species; and application to exotic forestry plantations or pastoral farmland. The aim of the study was to calculate the possible environmental impacts of the reuse options so the information can be used in a community dialogue process where the fate of the biosolids is decided upon. All reuse options showed improved environmental performance relative to landfilling. The direct application to land options showed the least environmental impact and the composting options had the most environmental impact. This is the first time this approach has been applied to biosolids management in New Zealand, and whilst there are limitations, the approach should be encouraged in other communities because it increases the engagement of the community with waste management decision-making and the environment.

Abstract: A fully sustainable sanitation system was developed for a rural hospital in Haiti. The system operates by converting human waste into biogas and fertilizer without using external energy. It is a hybrid anaerobic/aerobic system that maximizes methane production while producing quality compost. The system first separates liquid and solid human waste at the source to control carbon to nitrogen ratio and moisture content to facilitate enhanced biodegradation. It will then degrade human waste through anaerobic digestion and capture the methane gas for on-site use as a heating fuel. For anaerobic decomposition and methane harvesting a bioreactor with two-stage batch process was designed. Finally, partially degraded human waste is extracted from the bioreactor with two-stage batch process and applied to land farming type aerobic composter to produce fertilizer. The proposed system is optimized in design by considering local conditions such as waste composition, waste generation, reaction temperature, residence time, construction materials, and current practice. It is above ground with low maintenance requirements.

Abstract: The present research has focused on a contribution to the improvement of solid waste management in a waste collectors’ cooperative located in Brazil (Marcos Moura district, Santa Rita, Paraiba State) through a technical and organizational up-grading. Collection, processing and final disposal of wastes still represent a problem in some regions of Brazil. The proposed strategy foresaw the analysis of the local situation, the evaluation of the cooperative efficiency rate and then the introduction of technical and operational improvements to the service. Besides the technical activity, a social inclusion program was developed in order to include local scavengers (called Catadores) and to improve the social and economic conditions of populations involved in the process. The project also increased their environmental awareness. The workgroup is still monitoring the obtained results in order to check for the achievement of foreseen targets, to plan further improvements and to replicate this experience in other Brazilian areas.

Abstract: In this research article the sustainability of different practices to collect the metal fraction of household waste in the Helsinki metropolitan area, Finland is examined. The study is carried out by calculating and comparing the greenhouse gas reduction potential of optional practices for collecting the metal fraction of household waste in the Helsinki metropolitan area, Finland. In order to locate the greenhouse gas reduction potential of the separate collection of the metallic fraction of municipal solid waste (MSW) collected from residential sources, a comparative carbon footprint analysis using Life Cycle Assessment (LCA) on six different waste management scenarios is carried out. The modeled system consisted of a waste collection system, transportation, and different waste management alternatives, including on-site separation, separation at the waste management facility as well as metallurgical recovery of separated scrap. The results show that, in terms of greenhouse gas emissions, separate collection and recycling of the metallic fraction of solid MSW at residential properties is the preferable option compared to a scenario with no source sorting and incineration of everything. According to this research scenario where the metal fraction of solid household waste was not source-separated or collected separately have clearly higher greenhouse gas emissions compared to all the other scenarios with separate collection for metals. In addition, metal recycling by regional collection points has considerably lower greenhouse gas emission potential than metal recycling by collection directly from residential properties.

Abstract: Life Cycle Assessment (LCA) is a decision support tool that can be used to assess the environmental performance of an integrated waste management system or to identify the system with the best performance through a comparative analysis of different scenarios. The results of the analysis depend primarily on how the scenarios to be compared are defined, that is on which waste fractions are assumed to be sent to certain treatments/destinations and in what amounts. This paper reviews LCAs of integrated waste management systems with the aim of exploring how the scenarios to be compared are defined in the preliminary phase of an LCA. This critical review highlighted that various criteria, more or less subjective, are generally used for the definition of scenarios. Furthermore, the number of scenarios identified and compared is generally limited; this may entail that only the best option among a limited set of possibilities can be selected, instead of identifying the best of all possible combinations. As a result, the advisability of identifying an integrated life cycle-based methodological approach that allows finding the most environmentally sound scenario among all of those that are theoretically possible is stressed.

Abstract: Biosludge is a by-product of secondary wastewater treatment processes. Due to its high contents of organic carbon and plant nutrients, this bioresource can be practically reused as raw feedstock for making organic fertilizers and building materials. The objective of this paper was to provide a preliminary analysis of biosludge utilization in Taiwan, including food processing sludge, wine brewery sludge, textile sludge, pulp sludge and agricultural sludge. The discussion focused on the status of biosludge generation in recent years (2004–2010), and its sustainable management principle. This paper also presents updated information about the governmental regulations and policies for promoting these biosolids as material resources, as well as validating the regulatory levels of toxic constituents in the biosludge and its derived product (e.g., organic fertilizer). Based on the preliminary benefit analysis of utilizing biosludge as raw material for organic fertilizer, reusing biosludge, being a beneficial resource, should be superior to those by traditional treatments (i.e., incineration and sanitary landfill).

Abstract: Urban litter is generated by human societies everywhere. Some litter is recyclable waste. In this study, the acronym RMSW is used to refer to recyclable municipal solid waste generated in streets. Public attitude towards RMSW generation, generators’ perceptions, and quantification of RMSW in streets were examined in a Mexico City neighborhood, where litter presence causes major environmental problems affecting the population year after year. Interviews with neighborhood residents and item counts were carried out from 2010 to 2011. In all, 58% of interviewees reported generating RMSW at variable frequencies while 42% said they did not generate this kind of waste. Laziness, lack of vigilance by municipal authorities, no litter bins in streets, and imitation were the main causes identified by interviewees as reasons for littering. Potential litter generators may be of any age, educational level or income. Interviewees’ perception of RMSW generation was compared with item counts in the neighborhood studied.

Abstract: Waste costs the National Health Service (NHS) £71.2 million in 2007/2008; recycling all papers, newspapers and cardboard produced by the NHS in England and Wales could save up to 42,000 tonnes of CO2. As the largest employer in the UK, the NHS is in a prime position to both lead the way towards a sustainable future, but also act as a test bed for organizational change and provide evidence of what works at an individual level to change attitudes and behavior. However these require changes in mindset, including values, attitudes, norms and behaviors which are required along with clear definitions of the problems faced in terms of economics, society and culture. Initial investigations of the literature indicate that behavior change theory may provide a feasible means of achieving constructive changes in clinical waste management; such approaches require further investigation. This paper describes a feasibility study designed to examine issues that might affect the introduction of a behavior change strategy and improve waste management in a healthcare setting. Guided by the evidence gained from our systematic review, 20 interviews were carried out with senior managers, clinicians and support staff involved in the management of healthcare waste from a broad range of agencies in South West England. Interviews were audio-recorded and transcribed for analysis. Thematic content analysis was conducted in order to identify key issues and actions. Data extraction, coding and analysis were cross checked independently by the four members of the research team. Initial findings suggest tensions, between Government and local policies, between packaging and storage space at ward level and, and between the operational requirements of infection control and maintaining appropriate and ethical patient care. These tensions increase pressures on staff already trying to maintain high quality care in a resource restricted and changing environment.